Structural connectivity and its association with social connectedness in early adolescence

Challenges in replication: Does amygdala gray matter volume relate to social network size?

In this work, we tried to replicate and extend prior research on the relationship between social network size and the volume of the amygdala. We focused on the earliest evidence for this relationship (Bickart et al., Nature Neuroscience 14(2), 163-164, 2011) and another methodologically unique study that often is cited as a replication (Kanai et al., Proceedings of the Royal Society B: Biological Sciences, 279(1732), 1327-1334, 2012). Despite their tight link in the literature, we argue that Kanai et al. (Proceedings of the Royal Society B: Biological Sciences, 279(1732), 1327-1334, 2012) is not a replication of Bickart et al. Nature Neuroscience 14(2), 163-164 (2011), because it uses different morphometric measurements. We collected data from 128 participants on a 7-Tesla MRI and examined variations in gray matter volume (GMV) in the amygdala and its nuclei. We found inconclusive support for a correlation between measures of real-world social network and amygdala GMV, with small effect sizes and only anecdotal evidence for a positive relationship. We found support for the absence of a correlation between measures of online social network and amygdala GMV. We discuss different challenges faced in replication attempts for small effects, as initially reported in these two studies, and suggest that the results would be most helpful in the context of estimation and future meta-analytical efforts. Our findings underscore the value of a narrow approach in replication of brain-behavior relationships, one that is focused enough to investigate the specifics of what is measured. This approach can provide a complementary perspective to the more popular "thematic" alternative, in which conclusions are often broader but where conclusions may become disconnected from the evidence.

Understanding Wellbeing Profiles According to White Matter Structural Connectivity Sub-types in Early Adolescents: The First Hundred Brains Cohort from the Longitudinal Adolescent Brain Study

Wellbeing is protective against the emergence of psychopathology. Neurobiological markers associated with mental wellbeing during adolescence are important to understand. Limited research has examined neural networks (white matter tracts) and mental wellbeing in early adolescence specifically. A cross-sectional diffusion tensor imaging analysis approach was conducted, from the Longitudinal Adolescent Brain study, First Hundred Brains cohort (N = 99; 46.5% female; Mage = 13.01, SD = 0.55). Participants completed self-report measures including wellbeing, quality-of-life, and psychological distress. Potential neurobiological profiles using fractional anisotropy, axial, and radial diffusivity were determined via a whole brain voxel-wise approach, and hierarchical cluster analysis of fractional anisotropy values, obtained from 21 major white matter tracts. Three cluster groups with significantly different neurobiological profiles were distinguished. No significant differences were found between the three cluster groups and measures of wellbeing, but two left lateralized significant associations between white matter tracts and wellbeing measures were found. These results provide preliminary evidence for potential neurobiological markers of mental health and wellbeing in early adolescence and should be tracked longitudinally to provide more detailed and robust findings.

The relationship between adolescent reading habits and older adult social engagement - A longitudinal cohort analysis

OBJECTIVES

To investigate an access point during youth with the potential to have a positive impact on social engagement in later-life. Our social selves begin long before older adulthood, a life-stage during which people face extensive changes to their social milieu. Adolescence is a sensitive period for sociocultural processing and adolescent activities have the potential to impact social engagement in older adulthood. We examine reading since, in adolescence, it promotes social-cognitive skills which facilitate social engagement.

METHODS

Our main goal was to study the relationship between adolescent reading and older adult social engagement. We used longitudinal cohort data from Project Talent and ordered logistic regression as well as two-wave, cross-lagged panel model to analyze this relationship. Ancillary analyses examined recognized relationships between reading and social-cognition and between social-cognition and social engagement in both adolescence and older adulthood.

RESULTS

Adolescent reading was related to more frequent older adult social engagement with both family and friends. This relationship was independent of reading during older adulthood, social engagement during adolescence, and social-cognition at both life-stages. Adolescent social engagement was not associated with older adult reading in the two-wave, cross-lagged model. Reading was positively related to social-cognition in adolescence, but was insignificant in older adulthood. And, social-cognition was positively related to social engagement in both adolescence and older adulthood.

DISCUSSION

Reading is declining for both young and older Americans. Young Americans are also socializing less than in previous decades. These trends could have a detrimental influence on social engagement and social isolation in future cohorts of older adults. We recommend continuing to look for activities and experiences during youth, especially the sensitive period of adolescence, that could stimulate social engagement over the life-course and into older adulthood.